Small, Fluffy Monkeys Caught Whispering

Humans aren’t the only whisperers in the world, according to a new study that reveals cotton-top tamarins whisper too.

The news is like a page out of Disney, as these monkeys are small (they weigh just over 1 pound), intelligent and secretive, very cute and fluffy, and have distinctive hairdos. One would imagine that — if any animal whispers — it would have to be them.

Researchers Rachel Morrison and Diana Reiss of The City University of New York made the discovery after recording cotton-top tamarins housed at New York City’s Central Park Zoo. The findings are published in the latest issue of the journal Zoo Biology.

“We exposed a family of captive cotton-top tamarins to a supervisor who previously elicited a strong mobbing response,” they wrote. “Simultaneous audio–video recordings documented the animals’ behavioral and vocal responses in the supervisor’s presence and absence.”

Initially, these very low amplitude vocalizations eluded the researchers’ detection.

Careful analysis of the calls, when amplified, showed that the tamarins were whispering to each other.

You can listen to a bunch of different cotton-top tamarin calls at this page.

“Consistent with whisper-like behavior, the amplitude of the tamarins’ vocalizations was significantly reduced only in the presence of the supervisor,” Morrison and Reiss report.

It appears the monkeys were not happy to see this particular supervisor. They may have felt threatened by that individual’s presence and kept their voices down.

We don’t know what they were whispering, but it was probably something like, “Look over there. Be on your guard.” Most animals have alarm calls that communicate things like that, and can even be very specific, mentioning the type of threat, location and more.

Morrison and Reiss suspect that highly social and cooperative species, like the cotton-top tamarin, may be more likely to whisper.

It could also be then that many other non-human primates whisper. We just haven’t caught them doing it yet.